Response of dairy cattle to transient voltages and magnetic fields

Stray voltages in dairy facilities have been studied since the 1970s. Previous research using steady-state AC and DC voltages has defined cow-contact voltage levels which may cause behavioral and associated production problems. This research was designed to address concerns over possible effects of transient voltages and magnetic fields on dairy cows. Dairy cow response to transient voltages and magnetic fields was measured. The waveforms of the transient voltages applied were: 5 cycles of 60 Hz AC with a total pulse time of 83 ms, 1 cycle of 60 Hz AC with a total pulse time of 16 ms, and 1 cycle of an AC square wave (spiking positive and negative) of 2 ms duration. Alternating magnetic fields were produced by passing 60 Hz AC fundamental frequency with 2nd and 3rd harmonic and random noise components in metal structures around the cows. The maximum magnetic field associated with this current flow was in excess of 4 G. A wide range of sensitivity to transient voltages was observed among cows. Response levels from 24 cows to each transient exposure were normally distributed. No responses to magnetic fields were observed.< >